Cracked Heat Exchanger: What That Means and What You can Do Next

September 20, 2022

A furnace is almost always a background player for your home, keeping you warm across the cold winter months. It often won't be noticed until a malfunction appears.

One cause could be that your furnace has a cracked heat exchanger. It can be a safety risk, so it’s critical to familiarize yourself with the evidence of a cracked heat exchanger and what you can do if you are worried that is the problem.

What Is a Heat Exchanger in a Furnace?

A heat exchanger helps transition heat from the combustion chamber inside your furnace to the air that circulates inside the air ducts. It typically handles this with coils or tubes that heat up the air while serving as a barrier to keep gas created in the combustion chamber, called flue gasses, from getting out into your home.

Is a Cracked Heat Exchanger Dangerous?

Because of its central role, it isn't surprising that a broken heat exchanger can pose a risk. A damaged heat exchanger can enable dangerous gasses – like carbon monoxide, which can be lethal – to flow throughout your home.

For obvious reasons, do NOT turn on your furnace if you suspect there's a crack in the heat exchanger, as doing so could make the whole household sick. Contact an HVAC professional right away if you think your heater has a cracked heat exchanger that needs repair.

Four Warning Signs of a Cracked Heat Exchanger:

  • Furnace turns off: A crack in your heat exchanger can cause your furnace to turn off.
  • Odd Smells: If the air leaving your furnace has a powerful chemical scent, it could be evidence gasses are slipping through cracks in your heat exchanger. These gasses, which can smell like formaldehyde, are a significant warning sign.
  • Carbon monoxide alarm is triggered or you recognize symptoms of poisoning: If a cracked heat exchanger is relieving carbon monoxide in your home, your carbon monoxide alarm could go off or household members could start experiencing signs of carbon monoxide poisoning. Symptoms include headaches, dizziness, weakness, nausea, vomiting or feeling tired. If your alarm goes off or you feel unwell, get out of the home immediately and then call for help.
  • Soot: If you see black sooty buildup near the exterior of your furnace, it’s more evidence something could be seriously wrong.

What You Can Do if the Furnace Heat Exchanger is Cracked

If you worry your furnace has a cracked heat exchanger, contact a professional experienced in furnace installation Wharton as soon as possible so they can examine your system and, if necessary, handle a furnace heat exchanger replacement. Costs often vary depending on the situation, but estimates run in the neighborhood of $1,000 to $3,000.

Fortunately, the good news is that heat exchangers are often included in the warranty. It's a good idea to confirm the warranty paperwork on your furnace, since while the warranty won't always cover the entire cost of repairs, it can significantly reduce your bill.

How to Avoid a Cracked Heat Exchanger in Your Home

One of the most convenient ways to minimize the risk of problems in your furnace overall is with consistent furnace maintenance. Furnaces work the best when they work efficiently. Hiring a trained professional to check your furnace for worn-out parts, clogs in the air filters and other common problems can help you avoid getting a big bill later on.

It’s also a good idea to inspect your furnace filters every few months – it’s recommended some filters be swapped out every 90 days or sooner if they are dirty or grimy. While the filters aren't a part of the heat exchanger itself, the strain of drawing air through a clogged filter makes the entire furnace work longer to do its job. And the harder your furnace needs to run, the more deterioration parts like the heat exchanger will experience.